Electronic State of Low Spin MnAs(P)

The electronic state of the compound MnAs 1- x P x ( x =0.075) was investigated. It is in the low spin state below the Néel temperature (232 K), which is stabilized by the substitution of phosphorus in MnAs for arsenic. By analyzing the neutron magnetic scattering, the following results were obtained: (i) The magnetic structure is a double spiral structure with the propagation vector q =0.111× a * , and the magnetic moment is 1.80±0.05µ B at 78 K . (ii) By analyzing the anisotropy of the magnetic form factor, 3d electron configuration was determined as (1↑+1↓, 2↑, 0) for (ψ x 0 , ψ x ± , ψ u ± ) orbitals. (iii) This configuration explains qualitatively various changes in the physical properties occurring with the high spin-low spin transition. (iv) The radial distribution of 3d electron in the low spin state is more spread than that in the high spin state.